NATS Reactor Consumer

A reactor library for consuming from NATS.

• Consumer Client: A generic consuming client.
• Test Consumer: An example of a SpringBoot service using the client. Used for functional tests.

Monitoring

Monitoring: https://natsdashboard.com/jetstream?url=http%3A%2F%2Flocalhost%3A8222

Grafana: http://localhost:3000/dashboards

Metrics

• nats_processor_result: A counter for the result of a processed message. Has tag result that can be failed or success.
• nats_acked: A counter for number of messages acked.

Functional Tests

Here

• test_simple_message_is_processed: Ensures a message is consumed and acked.
• test_message_that_errors_goes_to_dlq: A message that continuously errors will go to a DLQ.
• test_message_that_does_not_ack_in_time_goes_to_dlq: A message that does not ack in time will eventually go to the DLQ.
• test_message_when_service_dies_it_is_retried: When the consumer dies during processing of a message, this message is retried.

Local Testing

1. Start NATS locally: cd deployments/local && make start
2. Build the test consumer: cd nats-reactor-consumer && make docker-build
3. Build the tests: cd functional-tests && make build
4. Run the tests: cd functional-tests && make run

Performance Tests

Here

The performance test sends requests to the test consumer and ensures that it processes the expected amount after 5 seconds from the test ending.

1. Start NATS locally: cd deployments/local && make start
2. Build the performance test image: cd performance-tests && make build
3. Start the test consumer: cd nats-reactor-consumer && make docker-run
4. Run the test: cd performance-tests && make run

Documentation

• NATS consumer properties: https://docs.nats.io/nats-concepts/jetstream/consumers
• NATS examples: https://github.com/synadia-io/rethink_connectivity
• NATS monitoring: https://natsdashboard.com/?url=http%3A%2F%2Flocalhost%3A8222